text: /*******************************************************************************
   * Copyright (c) 2016 Maxim Integrated Products, Inc., All Rights Reserved.
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included
   * in all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
   * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
   * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
   * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
   * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
   * OTHER DEALINGS IN THE SOFTWARE.
   *
   * Except as contained in this notice, the name of Maxim Integrated
   * Products, Inc. shall not be used except as stated in the Maxim Integrated
   * Products, Inc. Branding Policy.
   *
   * The mere transfer of this software does not imply any licenses
   * of trade secrets, proprietary technology, copyrights, patents,
   * trademarks, maskwork rights, or any other form of intellectual
   * property whatsoever. Maxim Integrated Products, Inc. retains all
   * ownership rights.
   *******************************************************************************
   */
  
  #include "mbed_assert.h"
  #include "cmsis.h"
  #include "pwmout_api.h"
  #include "pinmap.h"
  #include "clkman_regs.h"
  #include "PeripheralPins.h"
  
  #define MXC_GPIO_OUT_MODE_FIELD_WIDTH 4
  #define MXC_GPIO_OUT_MODE_FIELD_MASK  ((uint32_t)0xFFFFFFFF >> (32 - MXC_GPIO_OUT_MODE_FIELD_WIDTH))
  #define MXC_GPIO_FUNC_SEL_FIELD_WIDTH 4
  #define MXC_GPIO_FUNC_SEL_FIELD_MASK  ((uint32_t)0xFFFFFFFF >> (32 - MXC_GPIO_FUNC_SEL_FIELD_WIDTH))
  
  
  //******************************************************************************
  void pwmout_init(pwmout_t *obj, PinName pin)
  {
      // Make sure the pin is free for GPIO use
      unsigned int port = (unsigned int)pin >> PORT_SHIFT;
      unsigned int port_pin = (unsigned int)pin & ~(0xFFFFFFFF << PORT_SHIFT);
      MBED_ASSERT(MXC_GPIO->free[port] & (0x1 << port_pin));
  
      int i = 0;
      PinMap pwm = PinMap_PWM[0];
  
      // Check if there is a pulse train already active on this port
      int pin_func = (MXC_GPIO->func_sel[port] & (MXC_GPIO_FUNC_SEL_FIELD_MASK << (port_pin * MXC_GPIO_FUNC_SEL_FIELD_WIDTH))) >>
                     (port_pin * MXC_GPIO_FUNC_SEL_FIELD_WIDTH);
      MBED_ASSERT((pin_func < 1) || (pin_func > 3));
  
      // Search through PinMap_PWM to find the pin
      while (pwm.pin != pin) {
          pwm = PinMap_PWM[++i];
      }
  
      // Find a free PT instance on this pin
      while (pwm.pin == pin) {
  
          // Check to see if this PT instance is free
          if (((mxc_pt_regs_t *)pwm.peripheral)->rate_length & MXC_F_PT_RATE_LENGTH_MODE) {
              break;
          }
  
          pwm = PinMap_PWM[++i];
  
          // Raise an assertion if we can not allocate another PT instance.
          MBED_ASSERT(pwm.pin == pin);
      }
  
      // Enable the clock
      MXC_CLKMAN->sys_clk_ctrl_7_pt = MXC_S_CLKMAN_CLK_SCALE_DIV_1;
  
      // Set the obj pointer to the propper PWM instance
      obj->pwm = (mxc_pt_regs_t *)pwm.peripheral;
  
      // Initialize object period and pulse width
      obj->period = -1;
      obj->pulse_width = -1;
  
      // Disable the output
      obj->pwm->train = 0x0;
      obj->pwm->rate_length = 0x0;
  
      // Configure the pin
      pin_mode(pin, (PinMode)PullNone);
      pin_function(pin, pwm.function);
  
      // default to 20ms: standard for servos, and fine for e.g. brightness control
      pwmout_period_us(obj, 20000);
      pwmout_write(obj, 0);
  
      // Set the drive mode to normal
      MXC_SET_FIELD(&MXC_GPIO->out_mode[port],
                    (MXC_GPIO_OUT_MODE_FIELD_MASK << (port_pin * MXC_GPIO_OUT_MODE_FIELD_WIDTH)),
                    (MXC_V_GPIO_OUT_MODE_NORMAL << (port_pin * MXC_GPIO_OUT_MODE_FIELD_WIDTH)));
  
      // Enable this PWM channel
      MXC_PTG->enable |= (1 << MXC_PT_GET_IDX(obj->pwm));
  }
  
  //******************************************************************************
  void pwmout_free(pwmout_t *obj)
  {
      // Set the registers to the reset value
      obj->pwm->train = 0;
      obj->pwm->rate_length = 0x08000000;
  }
  
  //******************************************************************************
  static void pwmout_update(pwmout_t *obj)
  {
      // Calculate and set the divider ratio
      int div = (obj->period * (SystemCoreClock / 1000000)) / 32;
      if (div < 2) {
          div = 2;
      }
      MXC_SET_FIELD(&obj->pwm->rate_length, MXC_F_PT_RATE_LENGTH_RATE_CONTROL, div);
  
      // Change the duty cycle to adjust the pulse width
      obj->pwm->train = (0xFFFFFFFF << (32 - ((32 * obj->pulse_width) / obj->period)));
  }
  
  
  //******************************************************************************
  void pwmout_write(pwmout_t *obj, float percent)
  {
      // Saturate percent if outside of range
      if (percent < 0.0f) {
          percent = 0.0f;
      } else if (percent > 1.0f) {
          percent = 1.0f;
      }
  
      // Resize the pulse width to set the duty cycle
      pwmout_pulsewidth_us(obj, (int)(percent * obj->period));
  }
  
  //******************************************************************************
  float pwmout_read(pwmout_t *obj)
  {
      // Check for when pulsewidth or period equals 0
      if ((obj->pulse_width == 0) || (obj->period == 0)) {
          return 0;
      }
  
      // Return the duty cycle
      return ((float)obj->pulse_width / (float)obj->period);
  }
  
  //******************************************************************************
  void pwmout_period(pwmout_t *obj, float seconds)
  {
      pwmout_period_us(obj, (int)(seconds * 1000000.0f));
  }
  
  //******************************************************************************
  void pwmout_period_ms(pwmout_t *obj, int ms)
  {
      pwmout_period_us(obj, ms * 1000);
  }
  
  //******************************************************************************
  void pwmout_period_us(pwmout_t *obj, int us)
  {
      // Check the range of the period
      MBED_ASSERT((us >= 0) && (us <= (int)(SystemCoreClock / 32)));
  
      // Set pulse width to half the period if uninitialized
      if (obj->pulse_width == -1) {
          obj->pulse_width = us / 2;
      }
  
      // Save the period
      obj->period = us;
  
      // Update the registers
      pwmout_update(obj);
  }
  
  //******************************************************************************
  int pwmout_read_period_us(pwmout_t *obj)
  {
      return obj->period;
  }
  
  //******************************************************************************
  void pwmout_pulsewidth(pwmout_t *obj, float seconds)
  {
      pwmout_pulsewidth_us(obj, (int)(seconds * 1000000.0f));
  }
  
  //******************************************************************************
  void pwmout_pulsewidth_ms(pwmout_t *obj, int ms)
  {
      pwmout_pulsewidth_us(obj, ms * 1000);
  }
  
  //******************************************************************************
  void pwmout_pulsewidth_us(pwmout_t *obj, int us)
  {
      // Check the range of the pulsewidth
      MBED_ASSERT((us >= 0) && (us <= (int)(SystemCoreClock / 32)));
  
      // Initialize period to double the pulsewidth if uninitialized
      if (obj->period == -1) {
          obj->period = 2 * us;
      }
  
      // Save the pulsewidth
      obj->pulse_width = us;
  
      // Update the register
      pwmout_update(obj);
  }
  
  //******************************************************************************
  int pwmout_read_pulsewidth_us(pwmout_t *obj)
  {
      return obj->pulse_width;
  }
  
  const PinMap *pwmout_pinmap()
  {
      return PinMap_PWM;
  }
  
  